Transmission tower



FIG. 1 is a perspective view of a transmission tower showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a top planar view thereof; and

FIG. 5 is a bottom planar view thereof. 

The ornamental design for a transmission tower, substantially as shown and described. 